Here in California, around Sacramento, I pay $3.99 for 500 mealworms. I usta buy 'em in 50s, for $1.49, and then $2.99 for 100. Seemed smartest to get the 500, because [ahem] I treat the chickens every day and 50 mealworms just didn't go very far with 7 chickens.

I buy 'em at a feed store. PetSmart does carry them (for reptiles and fish, I guess - they were surprised when I said I gave them to chickens), but they're much more expensive there. The feed store even sells mealworms in two sizes: mini and Giant. I don't buy the giant ones.

If you plan on feeding them regularly I would try to find the bait distributor and see what kind of deal you can work out, or start raising your own. The bait shops probably have a 100% (or more) markup.